Free user on Pro Sites doesn't have access to plugins

I just tested my Pro Sites setup and it worked great! The new user account and site were created perfectly.

But, when I log in as the new user, none of the plugins are available (i.e. the "plugins" menu option doesn't show up at all)

I'm wondering if this is because the test user is just a free account? (i.e. the default free account that Pro Sites sets up)

How to I make all plugins available to a Free user as they are with Pro users?

Thanks